Improvement in machines for making plumbago crucibles and other articles



2 Sheets$heet 1. E. T. DRAVO.

Machine for Making Plumbago' Cruoibles, and other Articles. No. 221,672. Patented Nov. 18, 1879.

v lll 2e amlmassw. (0 W 7234M NJETEHS. PHOTO-LITHOGRAPNER. WASHINGTONv D C 2 Sheets-$heet 2. E. T. DRAVO. Machine for Making Plumbago Orucibles, and other Articles.

No. 22] 72. Patented Nov. 18, I879.

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NFETERS, PHOTO-LITHOGRAFHER. WASHINGTON. D C.

UNITED STATES PATENT OFFICE.

EDWARD T. DRAVO, O'F PITTSBURG, PENNSYLVANIA.

IMPROVEMENT IN MACHINES FOR MAKING PLUMBAGO CRUCIBLES AND OTHER ARTICLES,

Specification forming part of Letters Patent- No. 221,672, dated November 1%, 1879; application filed September 22, 1879.

To all whom it may concern:

Be it'known that I, EDWARD T. DRAVO, of

Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and usefullmprovement in Machines for Makin g Plumbago Orucibles and other articles; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawings, forming a part of this specification, in which- Figure 1 is a front elevation of my improved crucible machine. Fig. 2 is a section, at x 00, Fig. l and Fig. 3 is a vertical section.

Like letters of reference indicate like parts in each.

My invention relates to the manufacture of plumbago crucibles, such as are used in the manufacture of steel, brass, and other metals.

To enable others skilled in the art to make and use my invention, I will now describe particularly its construction and mode of operation.

The machine has a strong frame-work, a, by which all of the Working parts are sustained. On it are two crossheads, b b, and two center stays, 0. Outside of the stays a is a sliding frame, d, composed of the cross-bars d and uprights (P. The ends of the cross-bars d are grooved or recessed at e, and slide on the ways e. The screw-stops d limit the movement of the frame (1 to any desired height, said movement being shortened by turning up and lengthened by turning down the screws. The lower stay, 0, acts as the stop.

In the center of the frame a is a vertical shaft, f, upon the upper end of which is the chuck g, while the lower end is stepped in a piston, f, which operates in the hydraulic cylinder h. On the shaft f is a fast-and-loose pulley, P, by which it is operated by the belt and pulley t" and i on the power-shaft The shaft f has a vertical movement through the pulley sufficient to carry the mold up to position. The pulley is connected to the shaft by a feather or spline. The shaft is operated by the hydraulic cylinder h, and raises the mold into position, the sliding frame 01, which acts to steady and guide the shaft, being also raised n, which is composed of the two arms a pivoted on the shaft o The shaft n is stationary, and mounted on the bracket 0, and its upper end may be held true by an additional bracket. The bracketo projects from the crosshead b, to which it is fastened by two arrns,0.

From the junction of the two arms 0 a third arm, 0 extends back to the power-shaft i, which passes up through it. On the upper end of the power-shaft i is a pulley. g, which, by means of the belt (1 operates the pulley m on the plunger shaft m, and thereby rotates the plunger.

The lateral motion of the plunger or former m in the mold l is obtained by means of the rods r t", which are pivoted to and extend from the swinging arms a to the side of the machine, where, being provided with racks r, they mesh into the pinionst, which are mounted on the shaft t, and are operated by the wheel t A spring catch or stop, u, engaging the wheel 25 holds the former m at its central position, and when it is necessary to move the former m in making a crucible, the stop a is first thrown out of hold. The former m in its lateral movement travels in the arc of a circle, the center of which is the shaft M. It is only necessary that it should go from the center to the side of the mold. To insure its certain stopping at the proper distance from the side of the mold, to obtain a proper thickness of crucible, there are two adjust-able stops, 1;, against which the two arms u come, and which stop them at the proper point. These stops 1) are adj ustable in the slots 12 by the clamps v and also may be lengthened or shortened by turning them in their threaded collars. Thus the lateral movement of the former l may be arrested at the center, or at any desired point at that side.

The mold I is made of any desired and suitable material, and is partible either vertically, as shown, or horizontally, at pleasure. \Vhen made as shown the two halves are held together by a ring, I.

It will be seen that the pulleys which turn the former m are smaller than those that turn the mold l. (onsequently the speed of the former is less than that of the mold.

The operation of my machine is as follows: The ball of plumbago-bateh is placed in the mold, and the belt 1 thrown on the fast pulleyf. The mold is then raised by the hy' draulic press h, which is of the usual wellknown construction, and operated by the workman in the usual way at any desired moment. As the mold rises the former m enters the batch at the center of the lamp, and when the mold has reached the moldin; position, which is at the highest point of its vertical movement, the workman, by turning the hamlwheel 1". causes the former m to move slowly from the center toward the side of the mold llntil the arms I! encounter the stops r, which determine the thickness of the sides of the mold. The former m is then drawn back to the center of the mold by reversing: the wheel t and securing: it there by the stop a. The chuck is permitted todescend to its lower position, the belt 1' thrown off the fast onto the loose pulley, the dogs 9 screwed back to release the mold, the mold removed from the chuck and taken apart, and, finally,the molded crucible removed to the dryingroom.

The advantages ofmy machine are that all of g the operations are performed by the machine and that none are left to the skill orjndgment of the workman, and that, therefore, the eracibles have the uniformity and perfection of finish that are present in machine-madearticles which are formed on the same pattern. In addition to this the cost of production is reduced. The operation of the machine is rapid. The efl'ect of the former, revolving by a positive and independent revolution from that of the mold and atdiflerent speed, is to give it a kneading, and smoothing action on the batch, which produces a very firm, compact, and smooth crucible.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. In the formation of crucibles and like articles by machinery wherein the former and mold are rotated, the method herein described of causing the former to have a kneading and smoothing action on the batch, the same consisting in rotating the former independently of and at a lower rate of speed than the mold, substantially as specified.

2. In a machine for forming crucibles and like articles, the combination of a verticallyadjnstable mold and a horizontally-swinging pivoted former, substantially as and for the purpose specified.

3. The combination, with a vertically-movable mold aml a horizontally-movable former, of two sets of adjustable stops, one set to limit the motion of the former and the other to limit the motion of the mold, substantially as and for the purpose specified.

In testimony whereof I, the said EDWARD T. DRAVO, have hereunto set my hand.

EDWARD T. DRAVO.

Witnesses:

A. (J. JoIINsroN, T. B. KERR. 

